The present invention relates to resistive exercising equipment and, more particularly, to an elastic tension exercising apparatus incorporating a multiple pass cable and pulley arrangement.
A variety of exercising devices have been proposed to build and maintain proper muscle conditioning. In most such devices, repetitive muscular exertions are performed against a controlled resistive force. Weight lifting is a common form of exercise against a controlled resistive force, and various machines have been developed for this purpose. More recently, sophisticated hydraulic and pneumatic systems have been developed. However, such machines are generally rather costly and occupy a substantial amount of space. They also tend to be specialized in purpose, requiring a large number of machines to exercise the different muscle groups of the body.
Low cost devices using springs or other elastic elements to supply a desired resistive force have also been proposed, and have enjoyed some degree of success. However, such devices have not been well accepted among serious exercisers because the level of resistance varies radically during a exercising stroke. This is caused by the proportional relationship between elongation and the resistive force produced by an elastic member. The force varies from zero at the beginning of an exercising stroke, when the element is unstretched, to undesirably high levels later in the stroke. Most modern exercise authorities agree that optimal physical results are achieved when a relatively constant resistive force is maintained throughout an exercising cycle.
Another problem with prior elastic systems is the difficulty of varying the resistive force to meet the requirements of a particular user or exercise. A user will typically benefit from an increase in resistive force after performing an exercise regularly for several days. However, the level of resistive force encountered with most prior devices can be increased only by adding or replacing elastic elements. This is particularly troublesome when the device is used in a gym or health club by people of different strength capabilities, or for exercising muscle groups of varying strength.
Therefore, it is desirable in many applications to provide a compact and inexpensive device for providing an adjustable resistive force which remains substantially constant throughout an exercising stroke.